1. Field of the Invention
The invention relates to a mouthpiece or tip for a smokable article. Such tips are used more particularly for the smoking of cigarettes and can, like a conventional filter tip, be arranged directly on the tobacco rod of the cigarette or constructed as a separate tip into which the cigarette can be inserted.
2. Description of the Prior Art
Such tips are known in many forms as filter tips, in other words they contain a filter material ad/absorbing by a physical/chemical method solid particles contained in the tobacco smoke. This filter material may also be used in conjunction with throughflow ducts which block in the course of time so that a corresponding modification of the draw resistance occurs adapted to the smoking operation (German OS No. 32 25 073). These flow ducts can be constructed as longitudinal grooves in the outer surface of a core which is filled with the filter material (German OS No. 32 16 667 and German OS No. 33 12 706).
It is also known to combine the filtering action of such filter materials with a ventilation effect, wherein the smoke is diluted by pure air drawn in from the outside (German OS No. 32 46 898, German OS No. 33 11 903). In such cases the desired draw resistance is achieved when smoking by a bunch of coarse fibres or by a lamellar, film or sheet material corrugated in the longitudinal direction and/or at least partly of fibrous construction (German OS No. 33 11 903) or by a thin-drawn stick of bonded substantially non-crimped filaments (German OS No. 32 46 898).
A tip for a cigarette is also known which comprises an element in the form of a small stick of closed-cell cellulose acetate with an incorporated capillary tube with open ends made of a synthetic plastic material. A plurality of grooves serving as throughflow ducts are distributed uniformly over the circumference of this stick-shaped element and extend from the ventilation zone of the covering paper to the outlet end of the tip (German OS No. 31 16 052).
A disadvantage in the known forms of embodiment is the use of a filter material or at least a stick-shaped element made of closed-cell cellulose acetate, since the production cost of such a tip is thereby greatly increased.
Finally from U.S. Pat. No. 2,833,289 a tip is known, which comprises a covering zone in the covering paper, and a tubular core made for example of a synthetic plastic material and comprising at its inlet side, directed towards the tobacco skein, a small inlet aperture and at its outlet side directed towards the smoker an outlet aperture.
This core consists of a simple cylindrical synthetic plastic material tube provided at the inlet side with a shielding plate provided with a small aperture. Apertures are also provided in the wall of this synthetic plastic material tube which are in alignment with the ventilation apertures in the covering paper, so that the pure air sucked in from the outside through the apertures in the covering paper and in the tubular wall of the synthetic plastic material tube mixes with the smoke drawn in from the skein of tobacco in the said tube and thus dilutes such smoke, in other words the concentration of the smoke reaching the smoker is substantially lower.
However, the simple construction of such a "ventilation element" has to be at the expense of the disadvantage that the draw resistance of the cigarette, especially in the case of high degrees of ventilation, is not in the desired range to which the smoker is accustomed. Also it is only possible to manufacture this tip non-continuously, so that its production costs are relatively high.